    
The main mathematical tool is an application of the non-stationary phase method as shown in [1]} estimating Eq. (REF ) for large \(|x|+|t|\) . The part of the result, according to which the spatial probability in \(B_{r}\)  tends to zero (see (REF )),
is a corollary to [1]} by the fact that \(\mathcal {C}^\infty _c(\mathbb {R}^3\setminus \lbrace 0\rbrace )\) , the set of \(\mathcal {C}^\infty \) -functions with compact support in \(\mathbb {R}^3\setminus \lbrace 0\rbrace \) , is dense in \(L^2(\mathbb {R}^3)\) . Rather analogously we prove in (REF ) the fact that asymptotically the spatial probability vanishes outside \(B_{|t|}\) .
